1. Field of the Invention
The present invention relates to a semiconductor device for performing the switching drive control of an output transistor, and to a switching regulator using this device.
2. Description of Related Art
FIG. 11 is a circuit block diagram depicting a conventional switching regulator. As shown in FIG. 11, an n-channel MOS (metal oxide semiconductor) field effect transistor 201a is used as the output transistor in the conventional switching regulator, and a gate voltage greater than the input voltage Vin is needed in order to switch on the transistor 201a. In view of this, the conventional switching regulator is provided with a bootstrap circuit (diode 203 and capacitor C2), and a boost voltage Vbst that exceeds the switching voltage Vsw in the switch terminal SW by the charging voltage (voltage obtained by subtracting the forward voltage drop Vf of the diode 203 from a constant voltage Vreg) of the capacitor C2 is supplied to a driver 202a for generating the gate voltage of the transistor 201a. 
Japanese Laid-open Patent Publication Nos. 2009-108115 and 10-014217 can be cited as examples of the prior art related to switching regulators.